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QUARRY MATERIALS OF NEW YORK IO3 



which are developed extensively in the northern Adirondacks and 

 are included in the Saranac formation of dishing. In places the 

 gneisses lose their usual foliated structure and when free of ad- 

 mixture with other contrasting gneisses are well suited for building 

 and engineering materials. They contain a predominant proportion 

 of the feldspar minerals, with moderate to small amounts of quartz 

 and little of the dark silicates in the form of hornblende and 

 diopside. Magnetite is a variable constituent, ranging up to 7 or 

 8 per cent in amount. The texture is fine and compact, the result 

 of crushing and to some extent of recrystallization of coarse 

 originals. 



The principal quarries in this area are situated on the ridge back 

 of the State Prison and Hospital grounds ; they have been worked 

 for the supply of building stone for these structures and to some 

 extent for other purposes. They belong to the firm of Allen & 

 Cunningham who have operated them under the name of the Danne- 

 mora Granite Co. 



There are two openings situated less than a mile from Dannemora 

 and from 300 to 400 feet above it. The more northerly one shows a 

 pink gneiss of fine grain, containing magnetite as the principal dark 

 ingredient, with more or less hornblende. There are occasional 

 bunches of the dark minerals and also bands of pegmatite. The 

 rock is jointed fairly regularly by two vertical veins running north- 

 south and east-west respectively. Two trap dikes cut the granite 

 just south of the quarry. The rock face is about 20 feet high. At 

 the second opening the granite has a similar character and shows 

 pegmatitic and dark-colored inclusions. A 4-foot trap dike inter- 

 sects the quarry face in an east-west direction. The face is 100 feet 

 long and 30 feet high. Jointing is prominent in two directions as 

 at the first quarry. The streaks and inclusions are the main handi- 

 cap to the working of the quarry for building purposes, although 

 by selection a good quality of material can be obtained. 



GRANITE IN THE TOWN OF WILTON, SARATOGA COUNTY 



A massive gray granite is found in the town of Wilton, Saratoga 

 county, about 2 miles north of Saratoga Springs. It outcrops on 

 the easterly-facing ridge which marks the first elevations of the 

 Precambric highland of the Adirondacks to the west of the Paleo- 

 zoic plain. The area is of unknown extent but to the north the 

 granite soon disappears, being succeeded by Grenville schists and 

 quartzites with bands of crystalline limestone. The granite has a 

 fine granular texture, the result probably of crushing of a much 



